1. Field of the Invention
The present invention relates to an improved automobile air conditioner for air-conditioning the interior of the passenger compartment of an automobile, and an object thereof is to improve the layout of an air filter for cleaning air for use in air-conditioning and workability in replacing air filters.
The present application is based on Japanese Patent Applications No. Hei. 11-85745, which is incorporated herein by reference.
2. Description of the Related Art
As known, an automobile air conditioner comprises a blower unit, a cooling unit and a heater unit that are disposed in series to each other with respect to a flow of air for use in air-conditioning. Among them, the blower unit disposed at an upstream end of the air flow incorporates a fan in a blower case and functions to send air taken thereinto from the outside or inside of a vehicle compartment for use in air-conditioning to a downstream side of the air flow. The cooling unit disposed at an intermediate portion of the air flow incorporates therein an evaporator for cooling the air so sent thereto. In recent years, an air filter is disposed on an upstream side of the evaporator for trapping thereat foreign matters such as pollen contained in the air taken for use in air-conditioning. The heater unit disposed at a downstream side of the air flow incorporates therein a heater core for heating the air. A bypass flow path is provided on one side of the heater unit, and an air mixing door is provided upstream of these heater core and bypass flow path.
In air-conditioning the inside of a passenger compartment of an automobile with an automobile air conditioner constructed as described above, the fan is operated, and a refrigerant and hot water are allowed to flow through the evaporator and the heater core, respectively. The temperature of air taken in for use for air-conditioning is reduced and water vapor contained in the air is removed when it is allowed to pass through the evaporator (in a case where a refrigerant is allowed to flow through the evaporator), and the air so cooled and dried is then sent into the heater unit. In the heater unit, the air is allowed to pass through one or both of the heater core and bypass flow path so as to be adjusted at a desired temperature in accordance with a position of the air mixing door, and the air whose temperature is so adjusted is then blown into the automobile passenger compartment.
In recent years, there is a tendency to attempt to improve the efficiency in assembling of automobiles by integrating constituent units of an automobile air conditioner into one body. In other words, conventionally, a blower unit, a cooling unit and a heater unit are first constructed as a separate unit, respectively, and afterwards they are combined together. Recently, however, in contrast to this conventional method, there is a growing tendency to integrate the whole or part of the respective constituent units (for instance, the blower unit and the cooling unit) into one body with a view to omitting or simplifying the unit combining work. On the other hand, the respective constituent members of the automobile air conditioner need to be constructed so as to be disassembled when there is caused a failure thereof. In addition, air filters need to be replaced periodically, and therefore they are constructed so as to easily be mounted and dismounted to facilitate the replacement work. With a view to satisfying such a requirement, there is described and known in Japanese Patent Publication No. Hei. 10-181341 a conventional construction for facilitating the replacement of air filters.
However, in a case where the respective constituent units are integrated into one body, if there is a failure of a constituent component, it is difficult to dismount only the unit incorporating therein the failed component. For instance, in trying to do repair or replacement of an evaporator constituting the cooling unit, since it is not possible to remove only the cooling unit, cost involved in the repair or replacement of the failed evaporator would be increased. Or, in trying to retrofit an evaporator to an automobile heater which is not fitted with an evaporator, the retrofitting of the evaporator becomes difficult. To cope with this, it has been conceived to form an opening in a side of a case constituting the cooling unit so that only the evaporator can freely be removed from or installed in the cooling unit case through the opening so formed.
In a case, however, where a construction as described above is adopted, depending on the configuration of piping attached to the evaporator, it becomes difficult to dispose an air filter on the upstream side of the evaporator without any modification. In other words, a downstream end of a feed pipe for feeding a refrigerant into the evaporator and an upstream end of a withdrawal pipe for withdrawing the refrigerant from the evaporator are respectively connected to the evaporator. In a case where those end portions of the two pipes are connected to the evaporator at end portions in a width direction thereof, these two pipes do not disturb the disposition of the air filter. However, an evaporator provided with the aforesaid piping is not common currently. In contrast to this, in piping commonly used on the evaporator, pipes are connected to a side of a tank constituting the evaporator at an intermediate portion thereof and the pipes so connected are disposed upstream of the evaporator 1. With this construction, without any modification in the piping, the pipes so disposed interfere with the air filter and therefore it is not possible to dispose the air filter at a position immediately in front of the evaporator on the upstream side thereof. If the air filter is disposed far away from the evaporator, the air filter can be disposed at the aforesaid position. This would, however, increase a longitudinal dimension of the cooling unit along a direction in which air for use in air-conditioning is caused to flow, and hence leads to an enlargement of the automobile air conditioner, which is undesirable.